This invention in embodiments is generally directed to imaging members, and more specifically, the present invention in embodiments is directed to multilayered photoconductive imaging members with a hole blocking layer comprised, for example, of polymers, particularly copolymers of an aminoalkyltrialkoxysilane, such as 3-aminopropyltrialkoxy silane (g-APS) and an aminodialkyldialkoxysilane, such as 3-aminopropyl methyldiethoxysilane (2-APS), copolymers of an aminoalkyltrialkoxy silane and a dialkoxydialkylsilane, such as diethoxydimethylsilane or copolymers of an aminoalkyltrialkoxysilane, and a silane, such as a monoalkoxy silane, a dialkoxy silane, a tetraalkoxy silane, and the like. The hole blocking layer is in embodiments in contact with the supporting substrate and is preferably situated between the supporting substrate and the photogenerating layer comprised of photogenerating pigments, such as those illustrated in U.S. Pat. No. 5,482,811, the disclosure of which is totally incorporated herein by reference, especially Type V hydroxygallium phthalocyanine.
It is believed, although not being desired to be limited by theory, that the chemistry of amino-alkyl substituted trialkoxysilanes is dissimilar in both rate and scope from that of other trialkoxysilanes primarily because of the ability of the amino group to function as an internal catalyst in the reactions of these materials. A specific example of an amino-alkyl substituted trialkoxysilane disclosed herein is 3-aminopropyltriethoxysilane (γ-APS, gamma-aminopropyltriethoxysilane) which can undergo sol-gel type chemistry, and thus can be assumed to hydrolyze and condense in the presence of water. Conceptually, this reaction can be considered as a series of equilibrium between partially hydrolysis and partially condensed species. Conditions present during the hydrolysis and condensation, and the nature of the reactant γ-APS may effect the final distribution of species present and hence an indication of the predominant reaction pathway and pertinent equilibria. Since g-APS is a trialkoxy silane, it is capable of forming not only linear polysiloxanes, but polysilsesquioxanes and polyoctahedralsilsesquioxanes (POSS).
The imaging members of the present invention in embodiments exhibit excellent cyclic/environmental stability, and substantially no adverse changes in their performance over extended time periods; minimal amounts of charge deficient spots (CDSs), for example such a member may contain as low as 10 CDSs whereas a member containing a blocking layer containing only 3-aminopropyltrialkoxy silane may contain over 100 CDSs. The aforementioned photoresponsive, or photoconductive imaging members can be negatively charged when the photogenerating layer is situated between the hole transport layer and the hole blocking layer deposited on the substrate.
Processes of imaging, especially xerographic imaging and printing, including digital, are also encompassed by the present invention. More specifically, the layered photoconductive imaging members of the present invention can be selected for a number of different known imaging and printing processes including, for example, electrophotographic imaging processes, especially xerographic imaging and printing processes wherein charged latent images are rendered visible with toner compositions of an appropriate charge polarity. The imaging members as indicated herein are in embodiments sensitive in the wavelength region of, for example, from about 500 to about 900 nanometers, and in particular from about 650 to about 850 nanometers, thus diode lasers can be selected as the light source. Moreover, the imaging members of this invention are useful in color xerographic applications, particularly high-speed color copying and printing processes.